[32phil]

The easiest way to remove the upper race is to remove the top plate (already removed in your picture) then turn the steering shaft until the sector/pitman arm stops moving. Then continue turning the steering shaft and the worm will "climb" up the sector shaft and push the upper race up and out. PB Blaster helps here. If it's not coming out you may be turning the wrong way. Also a heat gun on high will help soften the old grease. If it's badly rusted in place you may want to look for a better box.